1. Field of the Invention
This invention relates to a hand tool for facilitating detachment and retrieval of overhead mounted electronic detectors such as smoke and heat detectors for testing and maintenance purposes.
2. State of the Prior Art
Electronic heat and smoke detectors are in wide use, with millions of installed units presently in service in commercial, industrial and public buildings. Maintenance of these electronic detector units calls for periodic testing to verify that the detector sensitivity is within manufacturer""s specification. This is done on the premises by means of a test instrument designed for this purpose which checks the sensitivity of the detector and if necessary assists in returning the detector to the proper operational parameters. Also, the detector housing normally has a number of small openings intended to admit ambient air into proximity to or contact with the electronic sensor of the detector unit. These openings may be relatively small and in time become occluded by accumulation of lint, dust, cobwebs and the like. Proper maintenance of the installed detector units calls for removal and cleaning of the detector head to ensure unobstructed flow of air into the detector housing.
The detector units, however, are normally installed on or near the ceiling of the protected space for earliest detection of rising smoke and heat. In many public and industrial spaces the ceiling may be at a considerable height above the floor, making access to the detector units a challenge.
Each detector unit normally has a detector base which is fastened to a mounting surface such as a ceiling or wall surface, and a detector head which includes an electronic sensing assembly, for example, a smoke or heat sensor and related circuitry along with an audible and sometimes a visual alarm device, contained in a detector head housing. The detector head is typically twist locked to the detector base and can be separated from the base by turning though a short arc of rotation.
Manufacturers of the electronic detector units provide detector removal tools for use by maintenance personnel with an extension handle and a detector grip at one end which allow the user to reach, detach and lower a detector unit mounted high above and well beyond arm""s length reach of a maintenance person standing on the ground or floor under the detector unit being serviced. However, existing detector removal tools are designed to fit only specific detector units, typically the particular manufacturer""s detectors. The exterior housings of the many detectors in use vary considerably in size and shape. Some are relatively flat, circular housings of various diameters, while others are tapered or frusto-conical in shape and may be greater in height than in width or diameter. Maintenance crews encounter a variety of such smoke and heat detector units in the course of their work, and for this reason are forced to either maintain and carry an assortment of detector removal tools on hand or else use ladders and the like to climb up and reach the detector units.
What is needed is a universal detector removal tool which can replace the different removal tools supplied by the detector manufacturers.
The invention disclosed here addresses the aforementioned need by providing a universal detector removal tool with a tool head adjustable for gripping different sized and shaped detector head housings and equipped with a long handle for extending the reach of a user standing on a floor under the detector unit.
More particularly, this invention concerns a tool for removing overhead mounted electronic detectors such as smoke and heat detectors having a detector head including a detector housing supported to a detector base and disengageable therefrom by relative rotation of the detector head. The novel tool includes a tool head, a handle attached to the tool head for elevating the tool head into proximity to a detector head to be removed, and a number of grip elements arranged on the tool head for capturing the detector housing in frictional engagement when the tool head is urged against the detector housing, such that the detector head may be rotated relative to the detector base by turning the handle thereby to disengage or reengage the detector body and the detector base. The grip elements are reconfigurable on the tool head into any one of multiple grip patterns, each grip pattern being adapted to capture a differently shaped or sized detector housing. For convenience, the handle of the tool may be a telescoping handle adjustable between a maximum and a minimum handle length, and the handle may be detachable from the tool head.
In one form of the invention the grip elements are removably set in sockets defined in the tool head, and the grip elements may be rearranged among the sockets in any of multiple patterns selected for capturing differently shaped and sized detector housings, such that the tool is adaptable for removing detector heads of different models of electronic detectors. Each of the grip elements may be generally shaped as a cylindrical pin, and each of the grip elements preferably has a relatively high friction surface oriented for making frictional engagement with the detector housing.
It is preferred that the grip elements be arranged and configured to define a detector housing capture perimeter of diminishing size with increasing proximity to the tool head. In particular the grip elements may each have a housing contact surface, the contact surfaces of the grip elements defining therebetween a detector housing capture perimeter, the contact surfaces being mutually divergent such that the capture perimeter is of diminishing size with increasing proximity to the tool head thereby to better conform to tapering exterior surfaces of detector housings.
It is presently preferred to provide the detector removal tool with two concentric arrays of six sockets each, these arrays also being centered on a tool axis which also contains the longitudinal axis of the tool handle. The sockets may be spaced along a circle to define the six corners of an imaginary hexagon for a total of twelve sockets arranged at the corners of two generally concentric hexagons. The number and arrangement of the sockets on the tool head may vary, however.
In one particular form of the invention the grip elements are manually insertable into and manually removable from the sockets, and the grip elements are retained by a press fit in the sockets. The sockets may be blind bores angled relative to the tool handle such that the grip elements inserted therein are mutually divergent and together define an open basket-like structure with a wider open end and narrower base. The grip elements consequently present splayed or divergent grip surfaces towards the detector head being removed.
These and other features and improvements of this invention will be better understood from the following detailed description taken in conjunction with the accompanying drawings.